The DFT-B3LYP method,with the basis set 6-311G,was employed to calculate the molecular geometries and electronic structures of 45 nitroaromatic compounds.EHOMO、ELUMO、μ、ΔQR and V were selected as quantum chemical descriptors.The acute toxicity of these compounds to tetrahymena pyriformis along with the above descriptors was used to establish the quantitative structure-activity relationship(QSAR).The variables were reduced using stepwise multiple regression(SMR)method for the training set,and the statistical results indicated that the correlation coefficient and cross validation using leave-one-out(LOO)were 0.941and 0.862,respectively.To validate the predictive power of the resulting model,external validation was performed with R2ext and Q2extvalues of 0.914 and 0.824,respectively.These showed that the QSAR model had good stability and predictability.The study indicated that the acute toxicity increase with the increase of the volume and the decrease of the energy of the lowest unoccupied orbit.The substituted groups which have strong electron-accepting ability would enhance the toxicity.
